Sparky

We'll there's a change bar next to it, and I'd never seen before so

I knew about the 20mm tire allowance, that's why I asked the question. But since they're on 17" rims it doesn't really bring anything to the discussion.

olddragger

iTrader: (3)

the 17's with the 40 sidewall really give you some grunt coming out of a corner.
OD

ULLLOSE

iTrader: (1)

So do the the 18"s we run:
Tire Size Sidewall Diameter Circumference Rev/Mile Difference
225/45-18 4.0 in. 25.97 in. 81.59 in. 777 0.0% Stock OE
245/35-18 3.4 in. 24.75 in. 77.76 in. 815 -4.7%
245/40-17 3.9 in. 24.72 in. 77.65 in. 816 -4.8%

No idea why they went that way.... Could be cost as they are a four car team.

As far as weight the 245-40-17 Hoosier weighs 22 lbs and the 245-35-18 is 21 lbs. So I don't see a weight savings unless they can get a 17" wheel that weighs less than my 16.3 lbs 18X8 SSR comp. Only good reason I can come up with is cost.

olddragger

iTrader: (3)

Very true ULLLOSE-- the 35 sidewall 18" is just a little(insignificant amount) taller than my 235/40/17. I run road tracks and I like a little more sidewall than the 35 gives. I like a little more give when I hit the rumble strips and it seems that the 35 sidewall tire pressures rise faster than 40's (less volume?). Still they are dang good tires--wish Kumho would offer more sizes. 17's are cheaper all the way around. I run the enkei rpo2 wheel 17x8 and with my current RA1 235/40's my wheel/tire weight is 40lbs. Lug nuts and all. Aint the best but it aint bad either. Especialy since i got the wheels(new) and a qualifing set of the ra1's(lot's of 17"s out there) for a total of $700. Course I am playing and Ya'll aren't and that is what makes the differance.
rotor on
olddragger

Skinless

Where do you find the used RA-1's? I'm trying to find a set of 18's. I know they are harder to come by than 17's, but I'm hoping when Spring hits it won't be too difficult to find a used set for track days. They'll be going on my spare set of stock rims.

olddragger

iTrader: (3)

18's can be found. Buy a copy of Grassroots Magazine and in the back there are listings for people that deal in slightly used race tires.
Good luck
Olddragger